Copolyamide from terephthalic acid,dodecanedioic acid and dodecane diamine

ABSTRACT

An improved copolyamide is derived from terephthalic acid, at least one straight-chain alkanedioic acid having from 8 to 14 carbon atoms, the terephthalic acid constituting from 50 to about 90 mole percent of the acids, and at least one straight-chain alpha, omega-alkanediamine having from 6 to 14 carbon atoms. This copolyamide is useful as a molding resin and in the production of fibers.

United States Patent 1191 Campbell Oct. 22, 1974 [54] COPOLYAMIDE FROMTEREPHTHALIC 3,475,387 10/1969 Carter ct a1 260/78 R ACID, DODECANEDIOICC AND 3,647,761 3/1972 Ridgeway et a1 260/78 R DODECANE DIAMINE3,696,074 10/1972 Tsuda et a1. 260/78 R [75 Inventor: Robert w.Campbell, Bartlesville, OTHER PUBLICATIONS Okla. Yu et 211., Journal ofPolymer Science, Vol. 42, [73] Assignee: Phillips Petroleum Company,1960) 249457 B 1 'll kl' an esvl e a Primary Examiner-Harold D. Anderson[22] Filed: May 22, 1972 [21] Appl. N0.: 255,868 [57] ABSTRACT Animproved copolyamide is derived from tercph- 52 us CL 2 0 7 R, 2 0 7 S,2 w thalic acid, at least one straight-chain alkanedioic acid 260/312 Nhaving from 8 to 14 carbon atoms, the terephthalic 51 Int. Cl C08g /20acid constituting from to about 90 mole percent of 581 Field of Search260/78 R, TW the acids, and at least one Straight-Chain alphaomega-alkanediamine having from 6 to 14 carbon 5 References Cited atoms.This copolyamide is useful as a molding resin UNITED STATES PATENTS andin the production of fibers. 3.216965 11/1965 Cipriani 260/857 TW 8Claims, N0 Drawings COPOLYAMIDE'FROM TEREPHTHALIC ACID,

DODECANEDIOIC ACID AND DODECANE DIAMINE This invention relates to animproved copolyterephleast one straight-chain alkanedioic acid, and atleast one straight-chain alpha,omega-alkanediamine, each-as such or as apreformed salt with-at least one of the other monomers. Thesecopolyamides have properties which make them superior to both thehomopolyamide from terephthalic acid and the alkanediamine and thehomopolyamide from the alkanedioic acid and the alkanediamine. Thus,when compared with homopolyamides from terephthalic acid andalkanediamines, the copolyamides of this invention have better flowproperties, are considerably whiter, have lower polymer-melttemperatures and lower crystalline melting points that permit lowerfabrication temperatures, and have greater strength and toughness. Whencompared with homopolyamides from alkanedioic acids and alkanediamines,the copolyamides of this invention possess greater strength andstiffness. I

Although it is not desired that this invention be restricted by anyparticular theory, it is presently believed that the especiallydesirable combination of properties exhibited by the copolyamides ofthis invention results in part from the surprising finding that thesecopolymers contain block structures, i.e., structures in which recurringunits derived from the alkanediamine and terephthalic acid aresegregated from, not randomly mixed with, recurring units derived fromthe alkanediamine and the alkanedioic acid. Evidenceforthis blockcharacter of the copolyamides of this invention is provided by theobservation that the copolymers possess a high degree of crystallinitythroughout the range of terephthalic acid to alkanedioic acid ratiosused in their preparation, and particularly by the finding of twocrystalline melting endotherms in the differential thermal analysistrace of the copolymers.

The copolyamides of this invention are especially useful as moldingresins andin the production of fibers.

Accordingly, it is an object of the present invention to provide a newand improved copolyterephthalamide. It is an object of the invention toproduce a copolyterephthalamide having an improved overall balance ofproperties. Yet another object of the invention is to provide acopolyterephthalamide having high values for tensile strength and Izodimpact. Other objects, aspects, and advantages of the invention will beapparent from a study of the specification and the appended claims tothe invention.

Straight-chain alkanedioic acids applicable in the production of thecopolyamides of this invention can Time, minutes Temperature, C.

be represented by the formula HO C(Cl-l ),CO H,

- wherein x is 'an integer of about 6 to 12. Suitable alkanedioic acidsinclude suberic acid, azelaic acid, decanedioic acid, undecanedioicacid, dodecanedioic acid, 'tridecanedioic acid, tetradecanedioic acid,and mixtures thereof. Dodecanedioic acid is the presentlypreferredalkanedioic acid;

. Straight-chain alpha,omega-alkanediamines which can be used in theproduction of the copolyamides of this invention can be represented bythe formula -H N(Cl-l ),,Nl-l wherein y is an integer of 6 to 14. Ap-

'tut'e-about 50 to about 90 mole percent, preferably about to about molepercent, of the total amount of dicarboxylic acids employed.

The copolyamides of this invention can be prepared by heating. themixture of monomers and/or salts thereof at about 250 to about 350C.,preferably about 300 to about 340C, for about 1 hour to about 16 hours,preferably about 1.5 hours to 8 hours. The pressure normally reaches amaximum of not more than about 1,000 psig, preferably not more thanabout 600 psig, and is allowed to diminish by venting gaseous material,sometimes with the aid of an inert gas, the final heating beingconducted at a pressure as low as about 1 mm Hg, preferably in the rangeof about 10 to about 50 mm Hg. If desired, the mixtures of monomersand/or .salts can be heated at a lower temperature, e.g., about"molecular weight of the polyamide.

COMPARATIVE EXAMPLE A To a l-liter autoclave were charged 200 grams(0.548 mole) of the salt (pH 7.3) of 1,12-

dodecanediamine and terephthalic acid, 2.72 grams (0.0164 mole) ofterephthalic acid, and 45 grams of deionized water. Air was removed, andthe system was placed under 60 psig nitrogen and heated 1 ing manner:

in the follow- Comments 20 mm Hg pressure.

The pressure reached the range of 500 to 600 psig and was maintained inthat range during the first 5 hours by venting as necessary.

This polymer, hereinafter designated as Homopolyamide A, had apolymer-melt temperature of 295C, an

inherent viscosity of 0.82,.determined at 30C. in a dichloroaeetic acidsolution having a-polymer concentration of 0.5 gram per 100 milliliterssolution,- and a T, of 296C. The determinations of inherent viscosity,crystalline melting point (T,,,), and polymer-melt temperature (PMT) aredescribed in pages 41-50 of Sorenson and Campbell, Preparative Methodsof Polymer Chemistry, lnterscience Publishers, lnc., New York (1961 Asobtained in this and subsequent Examples,

cresol solution having a polymer concentration of 0.5 gram per 100milliliters solution, and a T,,, of 184C.

EXAMPLE 1 A copolyamide of this invention was prepared in the followingmanner. To an 'unstirred 'l-liter autoclave were charged 161.79 grams(0.4414 mole) of the salt (pH 7.2) of 1,12-dodecanediamine andterephthalic acid, 25.4 grams (0.l 104 mole) of dodecanedioic acid,22.12 grams (0.1104 mole) of l,l2-dodecanediamine, 0.33 gram (0.0055mole) of acetic acid, and 45 grams of deionized water. The mixture wasthen heated in the following manner under a nitrogen atmosphere at aninitial pressure of 60 psig.

Time, minutes Temperature, C.

Comments 30 -25-210' heated at an at least substantially uniform rate.1150 210 temperature maintained at least substantially constant. 60210-320 heated at an at least substantially uniform 'rate. 30 320temperature maintained at least substantially constant. 30 320 ventedslowly to atmospheric pressure. 30 320 slow nitrogen flush. 320 pressurereduced slowly to mm Hg. 320 20 mm Hg.

T, was determined by differential thermal analysis of samples usingaheatingrate of l0C. per minute in an inert atmosphere, and PMT wasdetermined by placing samples on a heated bar with a temperaturegradient.

COMPARATIVE EXAMPLE B To a l-liter autoclave were charged 100.20 grams(0.500 mole) of 1,-12-dodecanediamine, 115.15 grams (0.500 mole) ofdodecanedioic acid, and 45 grams of deionized water. Air was removed,and the system was placed under 60 psig nitrogen and heated in thefollowing manner:

Time, minutes Temperature, C.

The pressure reached the range of 500 to 600 psig and was maintained inthis range during the first 4% hours t by venting as necessary.

Comments The resulting copolyamide, herein designated as Copolyamide 1,had a crystalline melting point of 285C, a polymer-melt temperature of280C and an inherent viscosity of 0.74, determined at 30C. in adichloroacetic acid solution having a polymer concentration of 0.5 gramper 100 milliliters solution.

f EXAMPLE 11 Another copolyamid'e of this invention was prepared in thefollowing manner. To an unstirred l-liter autoclave were charged 145.70grams (0.3975 mole) of the salt (pl-l 7.4) of 1,12-dodecanediamine andterephthalic acid, 61.05 grams (0.2651 mole) of dodecanedi- The pressurereached the range of 500 to 600 psig and was maintained in this rangeduring the first 3 /2 hours by venting as necessary.

This polymer, hereinafter designated as Homopolyamide B, had apolymer-melt temperature of 235C, an inherent viscosity of 1.71,determined at 30C. in a macid,

'dodecanediamine, 0.40 gram (0.0066 mole) of acetic oie acid, 53.13grams (0.2651 mole) of dodecanedioic 53.13 grams (0.2651 mole) of 1,12-

acid, and grams of deionized water. The mixture was then heated in thefollowing manner under a nitrogen atmosphere at an initial pressure ofpsig.

Time, minutes Temperature, C.

Comments 60 -25-2l0 heated at an at least substantially uniform rate.

60 210 temperature maintained at least substantially constant.

60 ZED-320 heated at an at least substantially uniform rate.

- Continued 7 Time, minutes Temperature, C.

Comments The pressure reached the range of 500 to 600 psig and wasmaintained in this range during the first 4 hours by venting asnecessary.

The resulting copolyamide, herein designated as Copolyamide ll, had acrystalline melting point of 244C, a polymer-melt temperature of 250C.,and an inherent viscosity of 0.76, determined indichloroacetic acid asdescribed above.

The above Copolyamides l and ll and Homopolyamides A and B werecompression molded, and mechanical properties of the molded specimenswere determined as shown in Table l. Copolyamides l and ll arepolyamides within the scope of this invention. Homopolyamides A and Bare polyamides outside the scope of this invention.

As shown in Table l, the tensile strength of each of Copolyamides I andll was far superior to that of either of the homopolyamides.Furthermore,Copolyamides I TABLE I Copolyamide l l presently preferredcopolyamides also are white in color.

EXAMPLE in Tensile strength, psi 10590 8570 Elongation, 7o 64 57Flexural modulus", psi X 10* 327 327 lzod impact strength",

ft-lb/in notch 0.9 0.7 Color White White Homopolyamide A I y B 0.2 1.2Cream White ASTM D 638-68. ASTM D 790-66. ASTM D 256-56.

Time, minutes Temperature, C.

Comments 60 -25-210 heated at an at least substantially uniform rate.

60 210-280 heated at an at least substantially uniform rate.

30 280-320 heated at an at least substantially uniform N g rate.

60 320 temperature maintained at least substantially constant.

30 320 vented slowly to atmospheric pressure.

30 320 nitrogen flush.

15 320 pressure reduced slowly to 30 mm Hg.

30 320 30 mm Hg.

and 11, and particularly Copolyamide l, exhibited a bet- 60 an inherentviscosity of 0.64, determined in dichloroter overall balance ofproperties than did the homopolyamides. In general, the copolyamides ofthe present invention have a tensile strength of at least 7,000 psi,preferably at least 7,500 psi, a percent elongation of at least 40,preferably at least 50, a flexural modulus of at least 250,000 psi,preferably at least 300,000 psi, an lzod impact strength of at least 0.5ftlb/in notch, preferably at least 0.6 ft-lb/in notch. The

Tenacity 4.3 gpd Elongation l0 /r lnitial modulu 59 gpd Boilingwatershrinkuge' 7 "/1 ASTM D 2256-69. ASTM D 2l02-64.

Time, minutes Temperature, C. Comments 60 120-210 heated at an at leastsubstantially uniform 60 210-280 li ted at an at least substantiallyuniform 30 280-320 lifted at an at least substantially uniform 360 32021 55 6" flush.

EXAMPLE IV The pressure reached the range of to psig and To an unstirredglass reactor were charged 4.3980 grams (12 millimoles) of the salt(pl-l 6.9) of 1,12- dodecanediamine and terephthalic acid, 1.8420 grams(8 millimoles) of dodecanedioic acid, and 1.6039 grams ('8 millimoles)of 1,12-dodecanediamine. The mixture was then heated in the followingmanner under a nitrogen atmosphere.

was maintained in this range during the first 2% hours by venting asnecessary.

The white copolyamide thus produced had a polymer-melt temperature of225C. and an inherent viscosity of 0.56, determined in dichloroaceticacid as in Example l..The copolyamide exhibited the normal meltingendotherm at its crystalline melting point of 234C and Time, minutesTemperature, C. Comme nts was maintained in this range during the first4% hours by venting as necessary.

The cream colored copolyamide thus produced has a polymer-melttemperature of 240C. and an inherent viscosity of 0.41, determined indichloroacetic acid as in Example 1. The copolyamide exhibited thenormal melting endotherm at its crystalline melting point of 254C. andan additional crystalline melting endotherm at l83C. which could bequenched out and redeveloped by annealing, indicating the polymer tohave a block structure.

I The pressure reached the range of 15 to 20 psig and 35 an additionalcrystalline melting endotherm at 185C,

indicating the polymer to have a block structure.

EXAMPLE Vl To an unstirred glass reactor were charged 3.7250 grams (l2millimoles) of the salt (pH 6.6) of 1,8- octanediamine and terephthalicacid, 1.8420 grams (8 millimoles) of dodecanedioic acid, and 1.1540grams (8 millimoles) of 1,8-octanediamine. The mixture was then heatedin the following manner under a nitrogen atmosphere at an initialpressure of i0 psig.

Time, minutes Temperature, C.

Comments 150-210 heated at an at least substantially uniform rate. 2l0temperature maintained at least substantially constant. 210-320 heatedat an at least substantially uniform rate. 320 temperature maintained atleast substantially constant. 320 nitrogen flush. 320 30 mm Hg.

EXAMPLE v To an unstirred glass reactor were charged 4.3986 grams (l2millimoles) of the salt (pH 7.0) of 1,12- dodecanediamine andterephthalic acid, 2.0721 grams (9 millimoles) of dodecanedioic' acid,and 16030 I The pressure reached the range of 15 to 20 psig and grams (8millimoles) of l,l2-dodecanediamine. The

mixture was then heated in the following manner under a nitrogenatmosphere at an initial pressure of 10 psig.

and a very small, broad crystalline melting endotherm at 186C,indicating the polymer to have a block structure.

EXAMPLE Vll To an unstirred glass reactor were charged 3.7251 grams (l2millimoles) of the salt (pH 6.6) of 1,8- octanediamine and terephthalicacid, 1.3941 grams (8 millimoles) of suberic acid, and 1.1543 grams (8millimoles) of 1,8-octanediamine. The mixture was then heated in thefollowing manner under a nitrogen atmosphere at an initial pressure of10 psig.

2. A copolyamide in accordance with claim 1 wherein said terephthalicacid constitutes from about 60 to about 85 mole percent of the acids.

- 3. A copolyamide in accordance with claim 2 wherein said copolyamidehas a percent elongation of at least 40 when measured in accordance withASTM D 6338-68, a flexural modulus of at least 250,000 psi when measuredin accordance with ASTM D 790-66 and an lzod impact strength of at least0.5 ft.-lb./in.

notch when measured in accordance with ASTM D 256-56.

Time, minutes Temperature, C.

Comments The pressure reached the range of to psig and was maintained inthis range during the first 4 /2 hours by venting as necessary.

The resulting cream colored copolyamide had a polymer-melt temperatureof 260C. and an inherent viscosity of 0.52, determined in dichloroaceticacid as in Example I. The copolyamide exhibited the normal meltingendotherm at its crystalline melting point of 285C. and a very smallcrystalline melting endotherm at 189C, indicating the polymer to have ablock structure.

Reasonable variations and modifications are possible within the scope ofthe foregoing disclosure and the appended claims to the invention.

I claim:

1. A copolyamide suitable for use as a molding resin and consistingessentially of the polymeric condensation product of terephthalic acid,dodecanedioic acid, and 1,12-dodecanediamine, the terephthalic acidconstituting from about 50 to about 90 mole percent of the acids, saidcopolyamide having a tensile strength of at least 7,000 psi whenmeasured in accordance with ASTM D 638-68.

4. A copolyamide in accordance with claim 3 wherein said terephthalicacid constitutes about mole percent of the acids.

5. A copolyamide in accordance with claim 2 wherein said copolyamide isat least substantially white in color.

6. A copolyamide in accordance with claim 2 wherein said copolyamide isderived from a mixture of 1,12-dodecanediamine, dodecanedioic acid, andthe salt of 1,12-dodecanediamine and terephthalic acid.

7. A copolyamide in accordance with claim 6 wherein said mixturecontains about 1 mole percent acetic acid.

8. A copolyamide in accordance with claim 2 wherein said copolyamide hasa tensile strength of at least 7,500 psi when measured in accordancewith, ASTM D 638-68, a percent elongation of at least 50 when measuredin accordance with ASTM D 638-68, a flexural modulus of at least 300,000psi when measured in accordance with ASTM D 790-66 and an lzod impactstrength of at least 0.6 ft.-lb./in. notch when measured in accordancewith ASTM D 256-56.

1. A COPOLYAMIDE SUITABLE FOR USE AS A MOLDING RESIN AND CONSISTINGESSENTIALLY OF THE POLYMERIC CONDENSATION PRODUCT OF TEREPHTHALIC ACID,DODECANEDIOIC ACID, AND 1,12DODECANEDIAMINE, THE TEREPHTHALIC ACIDCONSTITUTING FROM ABOUT 50 TO ABOUT 90 MOLE PERCENT OF THE ACIDS, SAIDCOPOLYAMIDE HAVING A TENSILE STRENGTH OF AT LEAST 7,000 PSI WHENMEASURED IN ACCORDANCE WITH ASTM D 638-68.
 2. A copolyamide inaccordance with claim 1 wherein said terephthalic acid constitutes fromabout 60 to about 85 mole percent of the acids.
 3. A copolyamide inaccordance with claim 2 wherein said copolyamide has a percentelongation of at least 40 when measured in accordance with ASTM D638-68, a flexural modulus of at least 250,000 psi when measured inaccordance with ASTM D 790-66 and an Izod impact strength of at least0.5 ft.-lb./in. notch when measured in accordance with ASTM D 256-56. 4.A copolyamide in accordance with claim 3 wherein said terephthalic acidconstitutes about 80 mole percent of the acids.
 5. A copolyamide inaccordance with claim 2 wherein said copolyamide is at leastsubstantially white in color.
 6. A copolyamide in accordance with claim2 wherein said copolyamide is derived from a mixture of1,12-dodecanediamine, dodecanedioic acid, and the salt of1,12-dodecanediamine and terephthalic acid.
 7. A copolyamide inaccordance with claim 6 wherein said mixture contains about 1 molepercent acetic acid.
 8. A copolyamide in accordance with claim 2 whereinsaid copolyamide has a tensile strength of at least 7,500 psi whenmeasured in accordance with ASTM D 638-68, a percent elongation of atleast 50 when measured in accordance with ASTM D 638-68, a flexuralmodulus of at least 300,000 psi when measured in accordance with ASTM D790-66 and an Izod impact strength of at least 0.6 ft.-lb./in. notchwhen measured in accordance with ASTM D 256-56.